I have been renting movies on my MBP and a previous MBP for years, and have always been able to transfer the rentals to an iPhone. I always rent on the MBP and not the iPhone. However due to a NEW authorisation problem recently I have not been able to play these movies through the Apple TV (V2) like I have been doing. Others on the Internet have also started having this problem. I have to resort to airplaying the movie from the MBP over to the Apple TV, which is a royal pain. What's the point of having all this gear in the family room when I have to get up and go to the office and start the movie playing from there?! Anyway, also recently I have not been able to move rented movies to the iPhone. I have tried recursively chmodding the Shared folder as described here
http://support.apple.com/kb/TS1277
and it didn't help.
So now, if we go on a long road trip or flight, we can't bring the rented movies on an iPhone/iPad. This is a big problem. No I am not going to bring the laptop on the trip. The iTunes library is on an external disk on the LAN anyway.
Re the country comments, I'm in Canada.